CVE-2025-40279
Published Dec 6, 2025
Modified Apr 15, 2026
Description
In the Linux kernel, the following vulnerability has been resolved: net: sched: act_connmark: initialize struct tc_ife to fix kernel leak In tcf_connmark_dump(), the variable 'opt' was partially initialized using a designatied initializer. While the padding bytes are reamined uninitialized. nla_put() copies the entire structure into a netlink message, these uninitialized bytes leaked to userspace. Initialize the structure with memset before assigning its fields to ensure all members and padding are cleared prior to beign copied.
Is your site exposed to CVE-2025-40279?
Run a free security scan — no signup, results in seconds.
References
Other References
https://git.kernel.org/stable/c/218b67c8c8246d47a2a7910eae80abe4861fe2b7
https://git.kernel.org/stable/c/25837889ec062f2b7618142cd80253dff3da5343
https://git.kernel.org/stable/c/31e4aa93e2e5b5647fc235b0f6ee329646878f9e
https://git.kernel.org/stable/c/51cb05d4fd632596816ba44e882e84db9fb28a7e
https://git.kernel.org/stable/c/62b656e43eaeae445a39cd8021a4f47065af4389
https://git.kernel.org/stable/c/73cc56c608c209d3d666cc571293b090a471da70
Frequently Asked Questions
What is CVE-2025-40279? +
In the Linux kernel, the following vulnerability has been resolved:
net: sched: act_connmark: initialize struct tc_ife to fix kernel leak
In tcf_connmark_dump(), the variable 'opt' was partially initialized using a
designatied initializer. While the padding bytes are reamined
uninitialized. nla_put() copies the entire structure into a
netlink message, these uninitialized bytes leaked to userspace.
Initialize the structure with memset before assigning its fields
to ensure all members and padding are cleared prior to beign copied.
How do I check if I'm vulnerable to CVE-2025-40279? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.